<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            background-color: #bbb;
        }

        #canvas {
            background-color: #fff;
        }
    </style>
</head>

<body>
    <canvas id="canvas" width="400" height="400"></canvas>
</body>
<script src="./utils.js"></script>
<script src="./arrow.js"></script>
<script src="./ball.js"></script>
<script>
    window.onload = () => {
        var canvas = document.getElementById("canvas");
        var context = canvas.getContext("2d");
        // 创建鼠标
        var mouse = utils.captureMouse(canvas),
            // 创建一个箭头
            arrow = new Arrow(),
            vr = 2;


        arrow.x = canvas.width / 2;
        arrow.y = canvas.height / 2;

        (function drawFrame() {
            window.requestAnimationFrame(drawFrame, canvas);
            context.clearRect(0, 0, canvas.width, canvas.height);

            arrow.rotation += vr * Math.PI / 180;
            arrow.draw(context);
        }())
    };
</script>

</html>